JP2529994B2 - In-reactor inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to the inspection of internal structures such as a core support plate and the like inside a boiling water reactor (hereinafter referred to as BWR) for flaw detection. The present invention relates to an in-reactor inspection apparatus suitable for inspecting, and more particularly, to an in-reactor inspecting apparatus capable of automatically inspecting an in-reactor structure such as a core support plate.

(Prior Art) Generally, a BWR is configured as shown in FIG. 8, and a reactor pressure vessel 1 accommodates a core 2 submerged by a coolant 3, and the core 2 has a core support structure 4 It is supported by.

The core 2 is composed of a plurality of fuel assemblies (not shown), control rods and the like. The control rod drive mechanism 5 adjusts the degree of insertion of the control rods into the core 2, thereby controlling the core output.

The coolant 3 flows upward in the core 2 in the figure, and while the coolant 3 cools the nuclear reaction heat of the core 2 while being heated, it is heated and its temperature rises. The heated coolant 3 becomes a two-phase flow of water and steam, and is introduced into a steam separator 6 installed above the core 2.

The steam separated from the liquid phase in the steam separator 6 is introduced into the steam dryer 7 installed above the steam to become dry steam.

This dry steam is transferred to a steam turbine (not shown) of a turbine system via a main steam pipe 8 connected to the reactor pressure vessel 1 and used for power generation.

The steam that has worked in the steam turbine is introduced into a condenser (not shown), condensed and liquefied to be condensed water. This condensate is again supplied to the reactor pressure vessel 1 via a condensate purification system (not shown).
Returned inside.

On the other hand, the water separated by the steam separator 6 flows down through the downcomer section in the reactor pressure vessel 1 and is mixed with the above-mentioned feed water to be supplied below the core 2 again. These actions are repeated thereafter.

By the way, the core support structure 4 is configured as shown in FIG. 9, and a plurality of fuel assemblies are vertically inserted into a plurality of grids of the upper grid plate 9 to form an upper portion of each fuel assembly. Position.

A core support plate 10 arranged below the upper lattice plate 9 supports the lower parts of a plurality of fuel assemblies for positioning. The upper lattice plate 9 and the core support plate 10 are housed in a cylindrical core shroud 11.

The core support plate 10 is configured as shown in FIG. 10, and a plurality of reinforcing plates 13, 13 ... Are arranged in parallel in the diametrical direction in a cylindrical body 12 to reinforce the body 12, Reinforcement plate 13,13 ...
The two are connected and fixed by connecting rods 14 and 14, and a circular upper plate 15 is welded to the upper end of the opening of the case 12 by circumferential welding 16,
The upper plate 15 is provided with a plurality of support fitting holes 15a for fitting and supporting a lower portion of a support fitting of a fuel assembly (not shown).

There is a possibility that stress corrosion cracking may occur in the welded portion such as the circumferential weld 16 and the vertical weld 17 of the joint of the body 12 and its peripheral portion due to long-term reactor operation, and if this stress corrosion cracking develops, cracks may occur. , The core support plate 10 may be damaged.

In this case, the function of supporting the fuel assembly by the core support plate 10 may be impaired, impairing the operation of the reactor, and possibly causing a secondary disaster.

Therefore, not only the core support plate 10, but also various inspections and inspections of the core structure in the reactor pressure vessel 1 and various in-core equipments are extremely important.

However, since the inside of the reactor pressure vessel 1 is under a high radiation dose, it is impossible for an operator to directly approach the in-core structure and various in-core equipment to perform various inspections and inspections.

Therefore, in the inspection of the conventional reactor internal structure and the like, the inspection equipment is suspended from above the reactor pressure vessel 1 without going into the reactor pressure vessel 1.

For example, when inspecting the core support plate 10, it is common to insert a long pole having inspection equipment attached to the tip into the reactor pressure vessel 1 from above.

However, in such an inspection method, since the upper grid plate 9 is located above the core support plate 10, the upper grid plate 9 may interfere with the long pole.

Therefore, in order to ensure good inspection workability,
It is necessary to remove the upper lattice plate 9 from the reactor pressure vessel 1.

However, the removal of the upper lattice plate 9 means the removal of all the fuel assemblies and the control rods, and not only the attachment / detachment work is difficult but also the work takes a long time.

Furthermore, when the upper lattice plate 9 is removed and then mounted in the reactor pressure vessel 1 again, problems such as centering may occur.
If accurate centering is not performed, the insertion characteristics of the control rod may be impaired. Considering these points, removal of the upper lattice plate 9 should be avoided as much as possible.

(Problems to be Solved by the Invention) As described above, the conventional inspection method of the core support plate 10 is very difficult to perform the inspection work, and moreover, the work of removing the upper lattice plate 9 from the reactor pressure vessel 1 is required. Therefore, there is a problem that it is extremely difficult.

Therefore, the present invention has been made in consideration of the above circumstances,
It is an object of the present invention to provide an in-reactor inspecting apparatus that facilitates inspection work of in-core structures such as a core support plate and improves the work efficiency.

[Structure of Invention]

(Means for Solving the Problems) The present invention relates to an in-reactor inspecting apparatus capable of automatically inspecting an in-core structure such as a core support plate.

That is, the present invention provides an inspecting device for inspecting the internal structure of a nuclear reactor in which a telescopic arm tip is rotatable about an axis perpendicular to the arm axis and reciprocally movable in the axial direction. A holding part for holding, a main body for accommodating the arm in a main body case so as to be tiltable laterally, and a main body for supporting the main body so as to be rotatable around its axis by a support part case and at the side of the support part case. A support portion having a plurality of openable and closable support legs that are opened to stand on the in-core structure, and a positioning part that positions the upright position to erect the support part on the in-core structure. It is characterized in that the rotation and reciprocating operation of the inspection device by the holding portion, the tilting accommodation and extension / contraction operation of the arm, and the opening / closing operation of the support leg by the supporting portion can be remotely controlled.

(Operation) When the in-reactor inspection device is lowered onto the reactor internal structure, the installation position of the reactor internal inspection device on the reactor internal structure is positioned by the positioning unit, and each support leg of the support unit is remote. By operation, the legs are opened to the side of the support case to support the main body.

Further, the arm is tilted to the side of the main body by remote control, and is pivoted around the axis of the main body, the telescopic arm is expanded and contracted, and the inspection device is moved to the inspection target portion of the reactor internal structure or its vicinity.

Here, the inspection device is rotated or moved up and down by an appropriate remote operation of the holding unit, and a required inspection is performed by the inspection device.

Therefore, according to the present invention, since the inspection of the reactor internal structure can be performed by remote control, the work efficiency of the inspection can be improved and the radiation exposure dose of the inspector can be reduced.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. In FIGS. 1 to 7, the same parts as those shown in FIGS. 8 to 10 are designated by the same reference numerals.

FIG. 1 is a perspective view showing an overall configuration of an embodiment of the present invention. A rectangular tubular main body 20 is provided with a rectangular tubular supporting portion 30 having the same shape and size as the main body 20 and a slightly shorter axial length. The main body 20 and the supporting portion 30 are rotatably supported around the axis thereof, and the main body 20 and the supporting portion 30 are formed in such a size and shape as to vertically insert through the lattice which is a gap between the lattice plates of the upper lattice plate 9 shown in FIG. Has been done.

The main body 20 accommodates a telescopic arm 40 in a sideways (horizontal direction) tiltable body in a storage groove 22 of a vertical groove whose one end is opened and an upper end of a main body case 21 having a rectangular tubular shape, Arm 40
A holding part 50 is attached to the tip of the holding part 50, and an inspection device 60 for inspecting the core support plate 10 is rotatably and vertically movable on the holding part 50.

A disc-shaped large-diameter end portion 71 of the positioning portion 70 is coaxially fixed to the lower end of the support portion 30, and an insertion cylinder 72 having a smaller diameter than this is integrally coupled to the large-diameter end portion 71. There is.

In FIG. 1, reference numeral 80 is a hose containing a power supply line, an air hose and the like (not shown), 81 and 82 are underwater TV cameras, and 83 is a hanging ear for hooking a hook of a hanging rope (not shown).

As shown in FIGS. 2 and 3, the inserting cylinder 72 is provided with a plurality of supporting fitting holes 15a in the center of the disk-shaped upper plate 15 of the core supporting plate 10 or a control rod guide tube (not shown). The large-diameter end portion 71 is inserted into the opening end portion so that the large-diameter end portion 71 is brought into close contact with the supporting fitting hole 15a or the opening end peripheral portion of the control rod guide tube to position the main body 20.

Further, as shown in FIG. 1, the supporting portion 30 has four supporting legs 32a, 32b, 32c, 32 on each surface of a supporting portion case 31 having a rectangular tubular shape.
The d is arranged so as to be openable and closable so as to open to the side of the support case 31.

That is, each support leg 32a-32d is a leg rod 32a ₁ , 32b ₁ , 32.
c _1, a disc-shaped Ashitan 32a ₂ to the distal end of _{32d 1, 32b 2, 32c 2} , the upper surface center portion of the 32d ₂ swingably connected, these Ashitan 32a ₂ ~32d ₂
The lower surface of the fitting disk 32a ₃ , which is removably fitted into the supporting fitting hole 15a of the core support plate 10 shown in FIGS. 2 and 3.
32b _3, 32c _3, 32d ₃ is projected coaxially, each support leg 32a~32d
Can reliably stand on the upper plate 15 of the core support plate 12.

As shown in FIG. 4, each support leg 32a-32d is attached to each leg rod.
32a _{1 to} 32d ₁ are pivotally supported at their inner ends inserted in the support case 31 by shaft pins 33, 33 ... And their tips are connected to closing springs 34, 34. The support legs 32a to 32d are biased upward in the figure to close the side surfaces of the insertion cylinder 72 as shown by the alternate long and short dash lines in the figure.

In addition, the inner ends of the leg rods 32a _{1 to} 32d ₁ are connected to the wires 35, 3
5 is connected to a stopper 75 standing upright on a piston 74 that reciprocates in a cylinder 73 formed coaxially in the insertion cylinder 72, and a lower chamber of the cylinder 73 below the piston 74 is connected to the stopper 75. By exhausting with an exhaust tube (not shown), the piston 74 is resisted against the spring force of each return spring 34, 34.
Is lowered downward in the figure to open the support legs 32a to 32d horizontally.

The stopper 75 abuts against the lower surfaces of a pair of rollers 76 that are arranged so as to face each other in the left-right direction in the figure, whereby the rise of the piston 74 is restricted.

A turning motor 36 is fixed to the upper end of the support case 31 as shown in FIG.
It is fixed to the center of the bottom of the main body case 21 of 0, a bearing 37 is interposed between the upper end of the support case 31 and the lower end of the main body case 21, and the main body 20 is driven by the rotation motor 36.
Is able to turn around its axis.

An arm 40 that is tiltably stored in the storage groove 22 of the main body 20.
5, the central portion of the base end portion 41a of the main arm 41 is swingably supported by the lower end portion of the housing groove 22 of the main body 20, and the tilting fixed to the outer surface of the base end portion 41a. A connecting rod 43a of a piston 43 of an operation cylinder that moves up and down in the axial direction of the main body 20 is pivotally attached to the outer end of the lever 42.

Therefore, the up and down movement of the piston 43 causes the arm 40 to tilt in the lateral direction of the main body 20 in a substantially horizontal direction, and the storage groove 22
It is stored inside.

The arm 40 is configured as shown in FIG. 6, and supports a telescopic arm 44 having a rectangular tube shape in a main arm 41 having a rectangular tube shape so as to be retractable.

That is, the arm 40 is mounted inside the base end portion 41a of the main arm 41 and fixed to the rotary shaft 44a of the drive motor 44 fixed to the drive gear 4.
4b is fixed, and a driven gear 45 fitted to one end of a ball screw 45 coaxially built in the main arm 41 is fixed to the drive gear 44b.
biting a.

The ball screw 45 has a ball nut 46, which is screwed onto the outer periphery of the left end of the screw part in the drawing, is fixed in the main arm 41 via a flange 46a, while being screwed onto the outer periphery of the right end of the screw part in the drawing. The ball nut 47 is fixed to the square tubular base end portion of the telescopic arm 44, and this square tubular base end portion is inserted into the square tubular main arm 41 to regulate the rotation of the moving ball nut 47. There is.

Therefore, by driving the drive motor 44, the ball screw 45 rotates via the gears 44b and 45a, the moving ball nut 47 moves axially on the ball screw 45, and the telescopic arm 44 expands and contracts in the axial direction. To do.

The holding portion 50 fixed to the tip end of the telescopic arm 44 is configured as shown in FIG. 7, and a bearing 53 is provided between the upper case 51 and the lower case 52 fixed to the tip end of the telescopic arm 44.
Is intervening.

The rotating shaft 51b of the motor 51a which is built in and fixed in the upper case 51 is fixed to the center of the upper end of the lower case 52,
By driving the motor 51a, the lower case 52 rotates around its rotation shaft 51b.

A cylinder 54 for vertically moving the swinging piston 53 is formed in the lower case 52, and an upper hole 54 is formed in an upper side surface of the cylinder 54.
Further, a and a lower hole 54b are formed in the lower side surface thereof.

Also, a pair of air hoses 55 are installed in the upper and lower holes 54a and 54b.
a and 55b are airtightly connected to each other, so that the piston 53 is pushed downward by supplying compressed air from the upper hole 54a to the upper chamber of the cylinder 54, while supplying compressed air to the lower chamber of the cylinder 54 from the lower hole 54b. With this, the piston 53 is pushed upward and the piston 53 is swung in the vertical direction.

The lower end of the piston rod 53a of the piston 53 extends outward from the bottom wall of the lower case 52 and is fixed to a device case 61 containing the inspection device 60.
An inspection device such as 62 and the underwater TV camera 63 is built in, and the shooting direction of the underwater TV camera 63 is illuminated by the underwater light 62.

The underwater TV camera 63 may be replaced with another inspection device such as an ultrasonic flaw detector, or may be installed side by side, if necessary.

Therefore, the inspection device 60 can rotate around the rotation shaft 51b of the motor 51a and can move up and down by the piston rod 53a.

 Next, the operation of this embodiment will be described.

First, in the core support plate 10, fuel assemblies and control rods (not shown) at locations to be inspected, and fuel support fittings and control rod guide tubes (not shown) at locations to install the in-reactor inspection apparatus of this embodiment Are removed from the core support plate 10.

Next, the arm 40 of the in-reactor inspection apparatus of this embodiment is installed in the main body.
The support legs 32a to 32d are stored in the storage groove 22 of 20 and closed to the side surface of the support case 31.

Then, it is suspended by an overhead crane or the like via a suspension rope (not shown) hooked on the suspension ear 83 of the in-reactor inspection device and suspended in the reactor pressure vessel 1.

Then, after the inspection device inside the nuclear reactor is inserted through the lattices which are the gaps of the upper lattice plate 9, each support leg 32 is remotely operated.
When the legs a to 32d are opened and lowered onto the core support plate 10, the insertion cylinder 72 is inserted into the support fitting hole 15a of the core support plate 10 or the open end of the control rod guide tube for positioning. Done,
Each support leg 32a opened as shown in FIG. 2 and FIG.
~ 32d ensures that the body 20 is self-supporting.

Thereafter, the arm 40 is tilted in a substantially horizontal direction by remote control as shown in FIGS. 1 to 3, and then the drive motor 36 of the support portion 30 is rotated in a required direction to move the arm 40 to the main body 20.
The arm 40 is swung around and the arm 40 is moved in the direction of the inspection target location.

Next, the arm 40 is expanded and contracted by remote control to move the inspection device 60 to the inspection target location or its vicinity.

Then, by appropriately controlling the drive of the motor 51a and the piston 53 of the holding unit 50, the underwater light 62 illuminates, the underwater TV camera 63, 81, 82 to photograph the inspection target part and other parts, and to monitor (not shown). Project.

Therefore, it is possible to inspect the inspection location and the like of the core support plate 10 by monitoring the monitor.

After completion of the inspection, first, the telescopic arm 44 of the arm 40 is contracted to be housed in the housing groove 22 of the main body case 21, and the support legs 32a to 3a.
2d is closed on the side surface of the support case 31.

Next, the suspension rope is wound up, and the in-reactor inspection device is inserted through the lattice of the upper lattice plate 9 and pulled up.

Therefore, according to the present embodiment, since the core support plate 10 can be inspected by remote operation of the in-reactor inspection device, it is possible to reduce the radiation dose of the inspector.

Moreover, since it is not necessary to remove the upper lattice plate 9 in the reactor pressure vessel 1, the inspection work of the core support plate 10 is significantly facilitated and the inspection time can be shortened significantly. The efficiency of can be improved.

In addition, although the case where the core support plate 10 is inspected has been described in the present embodiment, the present invention is not limited to this, and as an inspection device for the core shroud 11 (see FIG. 9) and the upper lattice plate 9, for example. You may comprise.

〔The invention's effect〕

As described above, according to the present invention, since it is possible to inspect the reactor internals housed in the nuclear reactor by remote control, the inspection work efficiency is improved and the radiation exposure dose of the inspector is reduced. Can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of an embodiment of the present invention, and FIG. 2 is a partial plan view showing a state in which the in-reactor inspecting apparatus of the embodiment shown in FIG. 1 is standing on a core support plate. FIGS. 3 and 3 show a part of FIG. 2 in a longitudinal cross section, FIG. 4 shows a partial cross section of the support shown in FIG. 1, and FIG. 5 shows the tilted state of the arm shown in FIG. A front view, FIG. 6 is a vertical cross-sectional view of a part of FIG. 5, FIG. 7 is a vertical cross-sectional view of a part of the holding part shown in FIG. 1, and FIG. 8 is a BWR reactor. FIG. 9 is a vertical cross-sectional view showing a general structure, FIG. 9 is a vertical cross-sectional view of the core support structure shown in FIG. 8, and FIG. 10 is a partially cutaway perspective view showing a part of the core support plate shown in FIG. It is a figure. 20 …… Main body, 21 …… Main body case, 30 …… Supporting part, 31 ……
Support case, 32a to 32d …… Support legs, 40 …… Arm, 41
...... Main arm, 44 …… Extensible arm, 50 …… Holding part, 60…
… Inspection equipment, 70 …… Positioning unit.

Claims (1)

(57) [Claims] Claim: What is claimed is: 1. An inspection device for inspecting reactor internals in a nuclear reactor, wherein an extendable arm tip is rotatable about an axis perpendicular to the arm axis and reciprocally movable in the axis direction. A holding part for holding, a main body for accommodating the arm in a main body case so as to be tiltable laterally, and a main body for supporting the main body so as to be rotatable around its axis by a support part case and at the side of the support part case. A support portion having a plurality of openable and closable support legs that are opened to stand on the in-core structure, and a positioning part that positions the upright position to erect the support part on the in-core structure. An inside of a nuclear reactor characterized in that the operation of rotating and reciprocating the inspection equipment by the holding part, the tilting storage and expansion / contraction of the arm, and the opening / closing operation of the supporting leg by the supporting part can be remotely controlled. Inspection device.